A lot of the complaints here appear to actually be "if you download software, or run that software on Android, or on any third party hardware at all, it could b

A lot of the complaints here appear to actually be "if you download software, or run that software on Android, or on any third party hardware at all, it could be compromised", but with Signal singled out. For a given user, I don't understand how signing is better than a checksum under this threat model. Going online to download an app is not part of an established connection with that app, so an attacker could simply serve you a page of their choosing with a signature they issued. Verifying identity for an initial connection is definitionally what signatures can't solve. I think, maybe, the idea is that a signed app could reject communications from unsigned/mis-signed installations? So if someone has entirely hijacked your session and served you a fake app, you won't be able to communicate with the rest of the network. It sounds like a coherent model at least: you can protect single targets by verifying their software when they try to communicate. (If so, I don't understand how that meshes with the call to federate Signal, which would require it to accept signatures from outside parties. Is the idea something like a CA web-of-trust where only people approved by accepted signers can federate their apps?)